A novel high‐performance Bi‐based glass‐Al₂O₃ composite system for LTCC applications

Abstract A novel high‐performance Bi‐based glass‐Al 2 O 3 composite material was successfully developed for low‐temperature co‐fired ceramic (LTCC) applications. The compositional effects of the binary glass of Bi 2 O 3 ‐ZnO‐B 2 O 3 ‐Al 2 O 3 (BZBA)+CaO‐B 2 O 3 ‐SiO 2 (CBS) on the phases, microstructures, microwave dielectric properties, and densification mechanism of the 45 wt% glass‐55 wt% Al 2 O 3 composite specimens were systematically studied. The optimal glass composition that could yield a high relative density (98.2%) and superior dielectric properties ( ε r = 8.7 and tan δ = 1.2 × 10 −3 ) was confirmed to be 32.5 wt% BZBA+12.5 wt% CBS. Furthermore, based on the optimized composition, a complete fabrication process of the glass‐Al 2 O 3 composites by tape casting was performed, the sample was found to simultaneously have a low dielectric loss (1.0 × 10 −3 ), a high mechanical strength level (300 MPa), a high thermal conductivity (4.25 W/m·K), and outstanding chemical compatibility with Ag electrode. The results indicate that the sample of 32.5 wt% BZBA+12.5 wt% CBS‐55 wt% Al 2 O 3 is a promising candidate material for LTCC applications.